Commonly, a heavy-duty vehicle, such as, but not limited to, a work machine such as a tractor, and more particularly, an all-wheel or all-track drive tractor for agriculture, earthmoving and other uses, has a chassis comprised of one or more weldments. Such weldments typically include a plurality of mounting or locating pads and/or plates nominally positioned for surface-to-surface abutting contact with mating mounting pads and/or surfaces on an axle, axle housing, or axle assembly, hereinafter referred to as an “axle”. The axle may be of wrought metal, cast, and/or welded construction. Typically, the known mounting pads and/or plates are oriented horizontally and are connected together by connectors-such as bolts and nuts or other fasteners.
One problem that has been found to arise with the known chassis and axle arrangements is that the connectors are often subjected to substantial shear loads in addition to longitudinal loads, when the chassis and axle are aligned and “fit-up” or brought together for assembly, and subsequently during operation of the vehicle, as a result of tractive effort forces generated at the ground and track or wheel interface. The shear loads applied during fit-up have been found to be the result of several conditions which in particular can include normal manufacturing tolerance stack-ups, as well as deformation, warpage and/or distortion of the chassis weldment as a result of the heat generated by welding. Such conditions can result in the mounting pads and/or plates being mis-positioned and/or mis-aligned or skewed, relative to their nominal positions and orientations. Subsequently, during fit-up, substantial forces must be applied to bring the mating pads and/or plates together. If the pads and/or plates cannot be satisfactorily brought together, shims or spacers can be used therebetween. However, the amount and direction or manner of warpage or deformation may not be uniform between weldments or vehicles, such that the location, number of shims, and the fit-up will typically vary between vehicles, which can add complexity and increase assembly time. Additionally, while use of shims and spacers can reduce axial or longitudinal loading on connectors such as bolts, they will typically not be as effective for reducing shear forces acting transversely against the connectors.
Thus, what is sought is an apparatus and method for assembling a chassis weldment of a vehicle or work machine with an axle, which facilitates and improves fit-up, and allows reducing shear loads acting on connectors used for connecting the chassis and axle.